In addition to being a past producer and a future source of most of the 35 minerals and metals considered critical to the United States, Alaska currently contributes a globally significant amount of one of these vital metals – germanium.

While not a widely known metal, germanium has optical qualities that make it an important ingredient in fiber-optics, infrared optics, electronics and solar energy systems.

"The extensive use of germanium for military and commercial applications has made it a critical material in the United States and the rest of the world," the United States Geological Survey wrote in a report on critical minerals published at the beginning of 2018.

Due to this criticality, the United States and China have included germanium in their stockpile programs and the European Union included germanium in a list of raw materials of critical concern for its member countries in 2010.

Like many other critical metals, germanium is not mined as a primary metal.

"As a byproduct metal, the supply of germanium is heavily reliant on zinc production," the USGS penned in its report.

Alaska happens to be home to the world's largest producing zinc mine, Red Dog, and the concentrates shipped from there contain noteworthy quantities of germanium.

"Worldwide, primary germanium was recovered in Canada from zinc residues (concentrates) shipped from the United States (specifically, the Red Dog zinc-lead mine in Alaska and a previously idled zinc mine complex in Tennessee); in China, from zinc residues and coal from multiple sources; in Finland, from zinc residues (concentrates) originating in Congo (Kinshasa); and in Russia, from coal from domestic sources on Sakhalin Island in Sakhalinskaya Oblast'," the USGS penned in its critical minerals report.

Optical qualities

While germanium is an intrinsic semiconductor, the metal has several optical qualities – transparent to the infrared electromagnetic spectrum, can be formed into glass, has an exceptionally high refractive index and low chromatic dispersion – that drives most of its demand.

Roughly half of the 30,000 kilograms (66,140 pounds) of germanium consumed in the United States during 2017 was used in the infrared imaging devices widely used by the military and law-enforcement agencies.

"Infrared optical devices improve a soldier's ability to operate weapon systems in harsh conditions effectively, and they are increasingly used in remotely operated unmanned weapons and aircraft," the USGS inked in its germanium report. "Infrared optical devices are also used for border patrol and by emergency response teams for conducting search-and-rescue operations."

An extraordinarily high refractive index – the ability to bend light – is an important characteristic germanium lends to fiber-optic cables.

"Germanium is added to the pure silica glass core of the fiber-optic cable to increase its refractive index and minimize signal loss over long distances," the USGS explains.

This property is strengthened by germanium's low chromatic dispersion – the scattering of light passing through a medium.

"Chromatic dispersion is a serious consideration in long-haul optical fibers. Its effect is essentially to stretch or flatten the initially sharply-defined binary pulses of information. This degradation makes the signals (1s and 0s) more difficult to distinguish from each other at the far end of the fiber," M2 Optics Inc. CEO Kevin Miller explains.

The growing need to send and receive data continues to drive the demand for more fiber-optic cable and the germanium that goes in it.

Solar power generation and electronics are the other big drivers for growing germanium demand, accounting for 15 percent of the germanium used in the U.S. during 2017.

"Germanium substrates are used to form the base layer in multijunction solar cells, which are the highest efficiency solar cells currently available," according to the USGS.

These solar arrays, which have three layers of cells that use germanium and other critical metals, are much more expensive to build than the typical photovoltaic cell that primarily uses silicon to convert light into electricity.

The high-efficiency of the germanium infused solar cells make them preferred for space applications such as the Mars rovers.

"The solar cells are stacked in three layers on the rover's solar arrays and, because they absorb more sunlight, can supply more power to the rover's re-chargeable lithium batteries," NASA Jet Propulsion Laboratory explains on technologies to power space missions.

USGS said recent research could make similar high-efficiency solar arrays commercially viable on Earth, a potential driver for future germanium demand.

In mid-December, germanium metal was selling for around US$2,024 per kilogram and germanium dioxide was US$1,435.

Red Dog germanium

Due to being a byproduct metal that is credited to the refinery extracting the germanium from the zinc and lead concentrates, it is hard to pinpoint exactly how much germanium is produced at Red Dog each year.

Indicators are, however, that Red Dog's germanium production are significant in relation to the global market of this critical mineral.

Teck Resources Ltd. – which operates Red Dog and owns Trail Operations in southern British Columbia where zinc and lead concentrates from the Northwest Alaska mine are refined – is one of the world's largest integrated germanium producers.

While Red Dog is not Trail's only supplier, USGS said the majority of the germanium the refinery produces likely comes from there.

"Most of the germanium produced at metallurgical facilities at Trail, British Columbia, Canada, likely comes from sphalerite concentrates from the Red Dog district," the geological survey wrote.

While the quantity of germanium produced at Trail is guarded, it is considered globally significant.

A partial force majeure – unforeseeable circumstances that prevent someone from fulfilling a contract – on germanium output from Trail early in 2018 has pushed germanium prices up 31 percent, from US$1,757/kg at the time. Teck announced the force majeure in January to US$2,300/kg in March. The critical mineral has maintained a price above US$2,200/kg throughout 2018.

While new germanium supply was disrupted due to an explosion at Trail in January, it has been indicated that Teck was able to fulfill about 60 percent of its germanium contracts for 2018.

Repairs to the damaged facilities at Trail are expected in the near term.

Teck announced plans earlier this year to extend the life of the Red Dog Mine out to at least 2031, based on the 57.6 million metric tons of reserves averaging 13.6 percent (13.9 billion pounds) zinc, 3.9 percent (2.5 billion lb) lead and an undisclosed amount of germanium in the deposits currently being mined.

Aktigiruq, a large and high-grade zinc target roughly five miles northwest of the current operations, could extend the life of Red Dog 25 to 50 years deeper into the 21st Century.

Though Aktigiruq had not previously been drilled sufficiently to calculate an NI 43-101-compliant resource, it is estimated that this exploration target that Teck is aggressively advancing has somewhere between 80 million and 150 million metric tons of material averaging around 13 percent zinc and 4 percent lead.

Teck's 2018 exploration at Aktigiruq focused on completing the drilling needed to upgrade this target to a deposit that meets modern reporting standards.

Part of the same group of sphalerite-rich sedimentary exhalative (SEDEX) deposits that is currently being mined at Red Dog, Aktigiruq likely means Alaska will be a global germanium source for decades to come.

Germanium at Bornite?

While zinc deposits are the primary source for germanium and Red Dog is among the richest such stores on Earth, carbonate hosted copper deposits also sometimes have a germanium component to them and there is one such deposit in Alaska that could be a source of this critical metal in the not too distant future.

Although germanium is known to be found in carbonate hosted zinc-lead deposits, not a lot is understood about potential associations with this style of deposit carrying mostly copper. The critical metal, however, has a known affinity for chalcopyrite, a copper mineral, which raises the possibility that a large carbonate hosted copper deposit, such as the Bornite deposit at Trilogy Metals Inc's Upper Kobuk Mineral Projects in Northwest Alaska, could be a future germanium source.

With 6.4 billion lb of high-grade copper, Bornite has long been as a world-class deposit of this energy metal. This carbonate hosted deposit is now emerging as a likely future source of at least one critical metal, maybe more.

To find out more about this potential, Trilogy Metals has entered into a technical assistance agreement with USGS to research the distribution of critical elements in the carbonate-hosted Bornite copper deposit. This work will focus primarily on the potential germanium, rhenium, gallium and cobalt components of the deposit, all of which are on the list of metals critical to the United States.

Bornite has already proven to host a significant amount of the battery metal cobalt.

Bornite is estimated to host 182.4 million metric tons of inferred resource averaging 0.019 percent (77 million lb) cobalt, according to the maiden cobalt resource calculation released in early June.

The results from 18,470 meters of drilling completed over the past two years indicates that the quantities of both the copper and cobalt will substantially increase when a new resource is calculated for Bornite.

And, depending on the results from the USGS work there, this deposit could prove to host intriguing stores of germanium and other metals considered critical to the United States.

NASA/JPL/Cornell University, Maas Digital LLC

High-efficiency, germanium infused solar cells are used to power the Mars rovers, each of which is built with the mobility and toolkit to function as a robotic geologist on our neighboring planet.

Editor's Note: "Critical Minerals Alaska – Germanium" is the twelfth and final installment of a series of articles published in North of 60 Mining News that investigates Alaska's potential as a domestic source of minerals deemed critical to the United States. At least 29 of the 35 critical minerals and metals identified by the U.S. Geological Survey – antimony, arsenic, barite, beryllium, bismuth, chromium, cobalt, fluorspar, gallium, germanium, graphite, hafnium, indium, magnesium, manganese, niobium, platinum group metals, rare earth elements, rhenium, rubidium, scandium, tantalum, tellurium, tin, titanium, tungsten, uranium, vanadium and zirconium – are found in Alaska.

Due to the popularity of this series, North of 60 Mining News will be publishing "Critical Minerals Alaska", a magazine in the spring of 2019. This full-color magazine will include the information gathered during the research for this series and provide information on many of the other critical metals and minerals found across the state.